Faster than light travel (FTL) is a(n as-yet) fictional trope that is used to allow stories to happen on scales larger than a single solar system. Nothing we’ve found so far indicates that faster than light travel is possible, let alone practical, but it makes things like Star Wars, Star Trek, and Battlestar Galactica possible as stories.
As noted on TV Tropes, there are three broad ‘favorites’ when it comes to FTL:
- “Warp” Drives: the ship distorts space around it to go really fast, so it stays in this universe but breaks the laws of physics in ways we haven’t figured out how to yet. Star Trek has made this a household word.
- “Jump” Drives: the ship finds itself in a special point in space, does some math, pushes a button, and appears instantly at its destination. This is the kind that the Galactica uses.
- “Hyperdrives”: the ship somehow breaks out of our current universe into a place where the ‘speed of light’ is faster. Star Wars and Hitchhikers Guide to the Galaxy prefer this type of FTL.
Overall, the actual mechanics don’t effect the story, but it’s an interesting topic in and of itself. For as much information as you could possibly want, the fantastic website Atomic Rockets has a large page on it: http://www.projectrho.com/public_html/rocket/fasterlight.php